Which is a compound? nitrogen gas carbon dioxide gas oxygen gas hydrogen gas

Carbon dioxide

Explanation:

Substance which are formed by two or more chemical elements are called compound. In compounds constituent elements are chemically bonded.

Substances which are formed by two or more similar atoms are called molecules.

Among the given options:

Molecular formula of nitrogen gas is . Nitrogen gas is made of similar atoms,  so it is a molecule.

Molecular formula of hydrogen gas is . As hydrogen gas is made of similar atoms,  so it is a also molecule.

Molecular formula of carbon dioxide is . As carbon dioxide is made of two types of elements, so it is a compound.

Molecular formula of oxygen gas is . As oxygen gas is made of similar atoms,  so it is a also molecule.

h let me think

2h2o2--> 2h2o + o2

this reaction is of the spontaneous decomposition of hydrogen peroxide down into water and oxygen.

add 2 molecules of hydrogen peroxide and 2 molecules of water. since oxygen is naturally diatomic, the total number of atoms of each element is now the same on both sides of the equation so it is balanced.

this may not be entirely correct but let me know.